Changes in transport activity are often associated with change in the cell division cycle. The project proposed here examines the changes in tranport activity that occur during stimulation of lymphocytes by mitogens. Transport activity will be used as a functional index of changes in the lymphocyte plasma membrane induced by mitogens under a variety of conditions. It is hoped that this approach will provide information on the initial biochemical events of mitogen-induced stimulation. Transport activity will also be used to detect differential effects of mitogens on B cells and T cells. Techniques will also be developed for preparing membrane vesicles from the lymphocyte plasma membrane and for using such preparations in the study of the mechanisms of transport in lymphocytes.